This application discloses an invention that is related, generally and in various embodiments, to a power supply having a dual processor architecture and a method of using a power supply having a dual processor architecture.
In certain applications, high voltage, high current power supplies utilize modular power cells to process power between a source and a load. Such modular power cells can be applied to a given power supply with various degrees of redundancy to improve the availability of the power supply. A control system may be incorporated to act as an interface between a user of the power supply, the power supply itself, and any load applied to the power supply. For example, FIG. 1 illustrates various embodiments of a power supply (e.g., an AC motor drive) having nine such power cells. The power cells in FIG. 1 are represented by a block having input terminals A, B, and C; and output terminals T1 and T2. In FIG. 1, a transformer or other multi-winding device 110 receives three-phase, medium-voltage power at its primary winding 112, and delivers power to a load 130 such as a three-phase AC motor via an array of single-phase inverters (also referred to as power cells). Each phase of the power supply output is fed by a group of series-connected power cells, called herein a “phase-group”.
The transformer 110 includes primary windings 112 that excite a number of secondary windings 114-122. Although primary winding 112 is illustrated as having a star configuration, a mesh configuration is also possible. Further, although secondary windings 114-122 are illustrated as having a delta or an extended-delta configuration, other configurations of windings may be used as described in U.S. Pat. No. 5,625,545 to Hammond, the disclosure of which is incorporated herein by reference in its entirety. In the example of FIG. 1 there is a separate secondary winding for each power cell. However, the number of power cells and/or secondary windings illustrated in FIG. 1 is merely exemplary, and other numbers are possible. Additional details about such a power supply are disclosed in U.S. Pat. No. 5,625,545.
Any number of ranks of power cells are connected between the transformer 110 and the load 130. A “rank” in the context of FIG. 1 is considered to be a three-phase set, or a group of three power cells established across each of the three phases of the power delivery system. Referring to FIG. 1, rank 150 includes power cells 151-153, rank 160 includes power cells 161-163, and rank 170 includes power cells 171-173. A master control system 195 sends command signals to local controls and receives status/feedback information from each cell over fiber optics or another wired or wireless communications medium 190. Similarly, communications medium 192 is used by the master control system 195 for communications with a user of the power supply. Commands may be received from the user, and any status/feedback information may be transmitted back to the user. As with communications medium 190, communications medium 192 may be fiber optics or another wired or wireless medium. It should be noted that the number of cells per phase depicted in FIG. 1 is exemplary, and more than or less than three ranks may be possible in various embodiments.
FIG. 2 illustrates various embodiments of a power cell 210 which is representative of various embodiments of the power cells of FIG. 1. The power cell 210 includes a three-phase diode-bridge rectifier 212, one or more direct current (DC) capacitors 214, and an H-bridge inverter 216. The rectifier 212 converts the alternating current (AC) voltage received at cell input 218 (i.e., at input terminals A, B and C) to a substantially constant DC voltage that is supported by each capacitor 214 that is connected across the output of the rectifier 212. The output stage of the power cell 210 includes an H-bridge inverter 216 which includes two poles, a left pole and a right pole, each with two switching devices. The inverter 216 transforms the DC voltage across the DC capacitors 214 to an AC output at the cell output 220 (i.e., across output terminals T1 and T2) using pulse-width modulation (PWM) of the semiconductor devices in the H-bridge inverter 216.
As shown in FIG. 2, the power cell 210 may also include fuses 222 connected between the cell input 218 and the rectifier 212. The fuses 222 may operate to help protect the power cell 210 in the event of a short-circuit failure. According to other embodiments, the power cell 210 is identical to or similar to those described in U.S. Pat. No. 5,986,909 and its derivative U.S. Pat. No. 6,222,284 to Hammond and Aiello, the disclosures of which are incorporated herein by reference in their entirety.
Returning to FIG. 1, the master control system 195 includes a single processor which receives operational information (voltage, current, etc.) associated with the power supply, processes the information, and based on the processed information, generates commands to control the operation of the power supply.
In many applications, users and/or owners of a given power supply utilize information associated with the power supply to control the operation of one or more systems external to the power supply, and also utilize information associated with the one or more systems to control the operation of the power supply. For such implementations, the processor receives and processes the operational information associated with the power supply, as well as the information associated with the one or more systems external to the power supply.
For some of such applications, the single processor can still provide real time control of the power supply. However, for other applications in which there is a requirement of processing and providing of more external information, the single processor is limited in the amount of data that can be processed and provided while still maintaining real time control of the power supply.